LOUISA REBGETZ, PRESENTER: Before the days of air conditioners, houses in the Northern Territory were built to a more sustainable design. Nowadays those wanting to build a greener, cleaner house say it's like fighting a war to get approvals and to find someone to build it.

ANDREW SPIERS, HOMEOWNER: What I like about is it lets the outside in. It's like living in a tent, it's just like living in a tin tent on a stick basically.

HELEN SPIERS, HOMEOWNER: You are very close to what's happening with the weather and every time you look any direction in the house it's a picture.

LOUISA REBGETZ: Andrew and Helen Spiers are living in their dream house on a remote block near Darwin River Dam. The house is self-sufficient complete with rainwater tanks and solar power.

HELEN SPIERS, HOMEOWNER: We have a good system in; we don't need a backup generator. We only use about 10 percent in any one day of what power is available because it is always renewing itself.

LOUISA REBGETZ: The house has a large air-gap in the roof which helps stop heat radiating into the house.

ANDREW SPIERS, HOMEOWNER: It's got a high pitched roof so as a result this house doesn't have any perceptible radiated heat coming from the roof even in the hottest part of the day.

LOUISA REBGETZ: It's a design feature Andrew Spiers learnt about in the 1960s when he studied architectural design at University.

ANDREW SPIERS, HOMEOWNER: It's interesting to me that we knew these things in the 1960s but in the next century we're still not doing them.

LOUISA REBGETZ: The couple had a tough battle convincing others that the design of their dream home would work - it took them seven years to finally complete their house.

ANDREW SPIERS, HOMEOWNER: I got a lot of resistance because our modern building code starts with the premise that the whole house is going to be air conditioned so I found that the builders here don't like to do new things. It took me four years to find a builder who was interested.

ROBIN KNOX, COOL MOB: If builders can find work that is quick and easy in materials that they're very used to operating with such as bricks they will probably choose those quick and easy jobs that they know they can finish and move on to the next job.

LOUISA REBGETZ: In the Top End housing developments like these are becoming more and more common. Environmental groups say it shows a lack of vision and reluctance to think outside the traditional block housing designs.

ROBIN KNOX, COOL MOB: There is very little room for vegetation and that means that you end up with a whole suburb that is like a heat sink really because the air surrounding your house is hot and one wall radiates off onto the next. I think the suburb of Muirhead is an attempt to try and build more tropical-design style houses but we will have to wait and see how that turns out.

LEANNE COURTNEY, TENNANT CREEK BUILDER: Our clients are government bodies, service providers and they want homes that are going to be durable and cost effective.

LOUISA REBGETZ: But this is new ground for the company so they're seeking help from the experts. Ecosystem Homes in Queensland is helping builders move to more sustainable designs. They say there's an unmet public demand for more environmentally sustainable housing.

JEFF, ECOSYSTEMS HOME: Builders build what they have always done so what we had to do is create a program, a building system, designs allowing the smaller builder access to this type of building. It's a need because people are more educated now except the building industry build what they've always done.

LOUISA REBGETZ: Back in the 1930s the government architect of the day Benny Burnett built homes like these with the tropical climate in mind.

ELIZABETH CLOSE, NATIONAL TRUST NT: These are wonderful. You know you open them up and you are in touch with the outside you have a breeze. It's a very pleasant place to be.

LOUISA REBGETZ: Burnett House at Myilly Point influenced the design of the Spiers dream home at Darwin River Dam.

ANDREW SPIERS, HOMEOWNER: So he oriented his houses so that he could pick up the north-westerly breezes in the wet season and the south-easterly breezes in the dry season and where possible put no intervening walls across the airflow.

LOUISA REBGETZ: Elizabeth Close is the director of the Northern Territory Heritage Trust which maintains Burnett House. The beautifully designed and constructed building draws crowds of visitors interested in seeing how Darwin's top public servants used to live. Elizabeth Close isn't surprised architectural design has changed over time.

ELIZABETH CLOSE, NATIONAL TRUST NT: The real reason for the change is that we have, we've come to look at housing a different way. We needed to be a little bit more affordable and also I think we've moved to air conditioners.

LOUISA REBGETZ: But the Spiers family home is living proof life in the tropics can go on without air conditioning and the couple hope their home provides inspiration for others.

ANDREW SPIERS, HOMEOWNER: A lot of people like to visit this house because in their words this is something that they would of liked to have built but they were told was impossible to do.

HELEN SPIERS, HOMEOWNER: If you think outside the square you can make a really interesting house but it doesn't actually cost you a whole lot more to make and you are using materials that aren't easily found.